Trisector



y 1950 .1. w. JAMBURA 2,507,598

TRISECTOR Filed Oct. 20, 1947 lHlllmlm WHIHIHI IN VEN TOR.

Jafin A/Jamarez 8' make/r64 ATTD R N EYE Patented May 16, 1959 UNITED STATES PATENT OFFICE 3 Claims. (CI. 3375) This invention relates to instruments for mechanically dividing angles into equal parts, and in particular includes a plurality of bars pivotally mounted on a common center with means maintaining the bars in equal spaced relation in all positions.

The purpose of this invention is, primarily, to provide means for readily trisecting an angle by mechanical instrumentalities.

Various devices have been provided for bisecting angles and attachments have been provided on compasses and the like whereby both legs thereof are maintained at equal distances from a center, but it is diificult to divide some angles into three parts. With this thought in mind this invention contemplates an instrument having a plurality of pivotally attached bars with levers of equal length attached to two bars and slidably mounted on an intermediate bar, and wherein a plurality of sets of the bars and levers are combined to provide a common instrument.

The object of the invention is to provide means for pivotally mounting a plurality of straight bars on a common center in combination with a protractor wherein the bars may be set by the protractor on one side of the center to any suitable angle and the ends of the bars on the other side of the center will trisect the angle.

Another object of the invention is to provide an instrument for trisecting angles which is formed with a plurality of bars pivotally mounted on a common center in which the angle is equally divided on both sides of the center.

A further object of the invention is to provide a trisector for equally dividing angles which is of a simple and economical construction.

With these and other objects and advantages in view the invention consists in the new and novel combination, construction, and arrangement of parts as hereinafter more fully described, set forth in the claims appended hereto, and disclosed in the accompanying drawings forming part hereof, wherein:

Figure 1 is a plan view of the trisector showing the elements partly open.

Figure 2 is a view showing a side elevation of the trisector.

Figure 3 is a view showing an end elevation of the trisector.

Figure 4 is an exploded view with parts broken away showing the relative positions of the hubs of the bars mounted on the common center.

Figure 5 is a section through the common center pivot taken on line 5-5 of Figure 1, and with the ends of the bars broken away.

Figure 6 is a section on line 6-6 of Figure 1 with the ends of the bars broken away.

Figure 7 is a section on line 'I-'I of Figure 1 with the ends of the bars broken away.

Figure 8 is a section on line 88 of Figure 1 also with the ends of the bars broken away.

Figure 9 is a section through the outer ends of the bars taken on line 9-9 of Figure 1 with the upper part of the post shown in elevation.

Figure 10 is a similar section taken on line i3-I3 of Figure 1.

Referring now to the drawings wherein like reference characters indicate corresponding parts the trisector of this invention includes four straight bars pivotally mounted on a common center providing intermediate dividing bars It and II, and indicating side bars I2 and I3, with a protractor I4 mounted on one of the side bars, and with equalizing levers I5 and I6 spacing the bar II between the bars It and I3, and I! and I8, spacing the bar Ill between the bars II and I2.

The bars are pivotally mounted on a pin I9 forming a common center through hubs that are spaced as illustrated in Figure 4, wherein a hub 2|] of the bar I2 is on the bottom, a hub 2I of the bar II is positioned on the hub 20, a hub 22 of the bar I0 is positioned on the hub 2|, and a hub 23 of the bar I3 is positioned on the hub 22. The lower hub 20 of the bar I2 is provided with a recess 24 in which a head 25 of the pin I9 is positioned, and the hub 23 and pin I9 are provided with keyways in which a key I3a is positioned which prevents the pin turning when a knurled nut 26 on the upper end of the pin is tightened to clamp the bars in diiferent positions.

The instrument is provided with guide bars 21 and 28 that are pivotally mounted on the pin I9 through hubs 29 and 30, and these bars are held in alignment with the bars I0 and II by the levers I5 and I6, and I1 and I8 through posts 3| and 32 at the outer ends and intermediate posts 33 and 34. The guide bars 21 and 28 are slidably mounted in slots 35 and 36 in the outer posts 3I and 32 and 31 and 38 in the intermediate posts 33 and 34.

The end of the bar In is pivotally mounted on a pin 39 at the lower end of the post 34 through a hub 40 as shown in Figure 7, and the lever I6 is also pivotally mounted on the pin 39 through a hub 4|, in the lower surface of which is a recess 42 to receive a head 43 of the pin. The corresponding end of the bar II is pivotally mounted on a pin 44 at the lower end of the post 33 through a hub 45 having a recess 46 3 therein to receive a head 41 on the lower end of the pin, and the lever I1 is also pivotally mounted on the pin 44 through a hub 48 as shown in Figure 6. A spacer 49 is provided between the hubs 45 and 48.

The end of the bar 12 is pivotally attached to the lever l8 by a pin 50 through hubs and 52 on the bar and lever respectively as shown in Figure 8, and the pin, which has a head 53 on the upper end, is provided with a cap screw 54 that is threaded in the lower end, and the head of the cap screw is positioned in a recess 55 in the hub. The end of the bar [3 is pivotally attached to the lever in a similar manner.

The ends of the levers l5 and I'B are pivotally mounted through hubs 56 and 51 on a pin -58 at the lower end of the post 3| and these are held by a cap screw 59, the head of which is positioned in a recess Bl) in the hub 51. The ends of the levers l1 and I8 are pivotally mounted through hubs 61 and G2 on a pin 63 at the lower end of the post '32, and these are held by a cap screw 84 with the head thereof positioned in a recess 65 in the hub'SZ. A spacer 66 ,is provided between the hubs 61 and 62.

With the bars and levers pivotally mounted in this manner and with the protractor Id :mounted on the upper edge of the bar l3 and centered on the pin IS, the instrument may be opened and set with the bar 12 registering with o the degree of the angle desired, and with the bar I2 set in this position the bars I!) and I! will be equally spaced between the bars I2 and 43, thereby dividing the angle defined by the bars 12 and 13 into three equal angles.

The protr'actor 14 is provided with a double row of innumerati'ons with the numerals representing the degrees in the outer row running from 10 to 1'70, and the corresponding numerals in the inner row running from 170 to 10 whereby the triseoted angle and its component parts or angles may readily be determined.

The instrument may be made in various sizes and of any suitable material, and it 'will be understood that modifications may be made in the design and arrangement'of the parts without .departing from the spirit of theinvention.

What is claimed is:

1. An instrument for dividing angles comprising a plurality of bars, means pivotally mounting the bars on acommon center, said bars including side and intermediate bars, rearwardly extending guide bars aligned with the intermediate Tears, levers pivotally mounted on the ends of the bars and slidably mounted on the said guide bars, means pivotally connecting the ends of the intermediate bars to the guide bars, and a protractor 4 on one of said side bars positioned in operative relation with the other side bar.

2. In an instrument for dividing angles, a plurality of bars having hubs intermediate of the length thereof, a pin pivotally mounting the bars through the hubs thereof, said bars including indicating side and dividing intermediate bars, posts pivotally mounted in the ends of the bars, guide bars also pivotally mounted on the said pin and extending through slots in the posts at the ends of "the dividing bars, and pivotally connected levers pivotally mounted on the said posts and slidably mounted on the said guide bars through the pivotal connection of the levers.

3. In an instrument for dividing angles, the combination which comprises a pair of vertically positioned fiat indicating bars having hubs intermediate of the ends thereof, a pair of flat vertio'ally positioned intermediate dividing bars also having hubs intermediate of the ends thereof, a vertically disposed post having a head on the lower end and a thumb nut threaded on the upper end thereof on which the said indicating and dividing bars are pivotally mounted through the hubs thereof, said hubs being staggered vertically, rearwardly extended guide bars also pivotally mounted on said post and aligned with the said dividing bars, guide posts pivotally mounted in and carried by the rear ends of the dividing bars, said guide posts having slots therethrough through which the said guide bars extend, sliding posts carried by the outer ends of the said guide bars and having slots theret-hrough in which the said guide bars are positioned, and links of equal length pivotally connecting the said sliding posts to the rear ends of :said indicating and dividing bars whereby as the opposite ends of the said indicating bars are placed on two points the corresponding ends of the dividing bars assume positions equidistant from the said indicating bars thereby dividing the said distance between the said points into three equal parts.

JOHN W. JAMBURA.

REFERENilES CITED The following references are of record in the file of this patent:

UNITED STATE$ PATENTS Number 7' Name Date 1,966,110 Woods r July 10, 1934 2,054,503 Jambura Sept. 15, 1936 2,259,619 Cooper s Oct. 21, 1941 OTHER REFERENCES The Tr'lsection Problem, page 38, by Robert C. Y'a't'es. Copyright 1942. 

